Laminar flame speeds of mixtures of ethane, ethylene, acetylene, and carbon monoxide with small amounts of hydrogen addition at both atmospheric and elevated pressures were experimentally and computationally determined. It was found that the approximate linear correlation identified previously between the laminar flame speeds and an appropriate definition of the amount of hydrogen addition for ...

New combustion systems based on ultra-lean premixed combustion have the potential for dramatically reducing pollutant emissions in transportation systems, heat, and stationary power generation. However, lean premixed flames are highly susceptible to fluiddynamical combustion instabilities, making robust and reliable systems difficult to design. Lowswirl burners are emerging as an important tech...

The shapes (flame-sheet and luminous-flame boundaries) of steady nonbuoyant round hydrocarbon-fueled laminar-jet diffusion flames in still and coflowing air were studied both experimentally and theoretically. Flamesheet shapes were measured from photographs using a CH optical filter to distinguish flame-sheet boundaries in the presence of blue CO2 and OH emissions and yellow continuum radiation...

Methane is a climatologically important greenhouse gas, which plays a key role in regulating water vapour in the stratosphere and hydroxyl radicals in the troposphere. Recent findings that vegetation emits methane have stimulated efforts to ascertain the impact of this source on the global budget. In this work, we present the re-5 sults of high frequency (ca. 1 min −1) methane measurements cond...

An experimental and numerical study was performed on the interaction of combustible solid particles with atmospheric, strained, laminar premixed methane/air and propane/air flames in normal gravity. The study was conducted in the opposed-jet configuration in which a single flame was stabilized below the gas stagnation plane by counterflowing a mixture against an air jet. Into the flame were see...

The small radiant heaters that burn hydrocarbon fuels propane, butane, methane/natural gas and liquid hydrocarbon fuels are used widely because of their simple design, their portability, and the ready availability of fuels. The open flame heater presents obvious disadvantages as follows. An upset heater is a grave fire risk where the surroundings are flammable and this restricts usage in, for e...

The laminar flame speed of Dimethyl Ether (DME)/air mixtures at room temperature and atmospheric pressure were determined experimentally over an extensive range of equivalence ratios, with and without 15% nitrogen dilution, using Particle Image Velocimetry (PIV) and a stagnation flame burner configuration. The laminar flame speeds were determined by linear extrapolation of the measured referenc...

An experimental and computational investigation on the liftoff characteristics of laminar partially premixed flames (PPFs) under normal (1-g) and microgravity (μ-g) conditions is presented. Lifted methane–air PPFs were established in axisymmetric coflowing jets using nitrogen dilution and various levels of partial premixing. The μ-g experiments were conducted in the 2.2-s drop tower at the NASA...

A pulsed plasma source is used to stabilize lean premixed methane flames. Nitric oxide (NO) production is measured using probe sampling and chemiluminescence analysis. While the discharge is a potential source of NO, it is observed that the flame also consumes some NO. The NO production in the flame is modeled by use of a modified opposed diffusion flame simulation (OPPDIF), augmented by the in...